The objective of the proposed research are to both prepare and investigate prodrugs and polymeric chelating agents for use in the treatment of transfusion-induced iron-overload or hemosiderosis. The prodrugs to be investigated are (a) lipophilic derivatives of desferrioxamine that are designed for absorption across the intestinal mucosa and subsequent hydrolysis to the active form in the plasma and (b) high-molecular-weight conjugates of desferrioxamine that are designed for prolonged-action drug delivery in the plasma. The polymeric chelating agents are planned for use in either the blood stream or the gastrointestinal tract. We also propose to investigate iron mobilization from intracellular storage sites by the use of ionophores and to develop an improved hepatocyte assay for screening these compounds.